Model-experiment comparison for transverse loading of metal–composite ring specimen (Part 1)

Abstract

As a building block towards improved understanding and design of Composite Overwrapped Pressure Vessels (COPV), this paper presents simulations and experimental validation of a 3D finite element model for a metal–composite ring structure subjected to quasi-static indentation, used as a proxy for low velocity impact (LVI). The focus of the work is to model composite ply delamination as well as metal–composite separation, using cohesive elements. A methodology is presented to determine the parameters used for the traction-separation law that controls the cohesive elements. The model was calibrated and validated using a hybrid metal–composite ring at reasonable engineering length-scales, corresponding to structures with 159 mm outer diameter and 50 mm length. Each ring specimen was loaded in displacement controlled compression up to 20 mm, i.e. the point at which composite delamination and plastic deformation of the metallic layer has occurred. Validation is performed by comparing experimental force–displacement curves, strain fields and damage mechanisms to results obtained from the finite element (FE) model. Results from the numerical modelling are in good agreement with experimental values.